Thrombin generation correlates with disease duration in multiple sclerosis (MS): Novel insights into the MS-associated prothrombotic state.

Background: Thrombin is well recognised for its role in the coagulation cascade but it also plays a role in inflammation, with enhanced thrombin generation observed in several inflammatory disorders. Although patients with multiple sclerosis (MS) have a higher incidence of thrombotic disease, thrombin generation has not been studied to date.

Objectives: The aim of this study was to characterise calibrated automated thrombography parameters in patients with relapsing-remitting MS (RRMS) and primary progressive MS (PPMS) in comparison to healthy controls (HCs).

Methods: Calibrated automated thrombography was performed on platelet poor plasma from 15 patients with RRMS, 15 with PPMS and 19 HCs.

Results: We found that patients with RRMS generate thrombin at a significantly faster rate than the less inflammatory subtype, PPMS or HCs. In addition, the speed of thrombin generation was significantly correlated with time from clinical diagnosis in both subtypes. However, in RRMS the rate of thrombin generation was increased with increased time from clinical diagnosis, while in PPMS the rate of thrombin generation decreased with increased time from clinical diagnosis.

Conclusions: These data likely reflect the differential active proinflammatory states in each MS subtype and provide novel mechanistic insights into the clinically relevant prothrombotic state observed in these patients.